1. Field
The present invention relates to integrated circuits and, more particularly, to systems and methods for dynamically de-aging integrated circuit performance.
2. Background
Reducing integrated circuit power consumption has become increasingly important, particularly in battery-powered devices. Reducing the supply voltage can reduce power consumption. The minimum supply voltage needed to operate an integrated circuit can vary based on various conditions such as manufacturing variations, circuit characteristics, temperature, and operational modes of various modules in the integrated circuit. Adaptive voltage scaling (AVS) can be used to control the supply voltage based on sensed performance measures of the integrated circuit.
Device aging, particularly in nanometer technologies, results in degradation of the electrical parameters of an integrated circuit. For example, transistor threshold voltages can be increased by effects such as positive bias temperature instability (PBTI) and negative bias temperature instability (NBTI). Circuits generally operate more slowly with aging. This affects the supply voltage needed to operate the integrated circuit. The rate and amount of aging can vary with the usage of the integrated circuit. For example, a mobile phone may age more when the user uses the phone for multiple tasks such as texting, phone calls, streaming video, and playing games throughout the day compared to a user whose phone is in standby most of the day.
Prior aging compensation schemes estimate a priori the effect of aging on a device. Then, based on a worst-case scenario, aging effects are accounted for by including a large guard band so that the device meets its design requirements if the full effects of aging manifest themselves near the end of the expected operating life of the device. This results in an overly conservative design which can result in significant performance loss. In addition to increased power consumption, reliability can be reduced due to increased temperature.